Field of the Invention
The present invention relates to plumbing in a water closet or toilet water tank of a toilet, and more particularly to flush valve assemblies for use in the water tank of a toilet assembly.
Description of Related Art
Toilets and toilet assemblies for removing waste products are well known. Typically, toilets incorporate three systems that work together to perform the flushing action. Those systems are (1) the bowl, which includes a waste receptacle in fluid communication with a drain line (2) the flush mechanism, and (3) the refill mechanism. Working in concert, these three systems enable the flushing function of the toilet.
Usually, the toilet tank, positioned over the back of the toilet bowl in the toilet assembly, holds water that is used to flush waste from the toilet bowl, through a trapway and to a sewage drain line, as well as refilling the bowl with fresh water. When a user wants to flush the toilet, the user pushes down on a flush lever or other flush actuator on the outside of the tank, which is connected on the inside of the tank typically to a movable chain and/or lever. When the flush lever is depressed on the outside of the tank, the chain or lever on the inside of the tank acts to lift and open the flush valve, enabling water to flow from the tank into the bowl, thus initiating the toilet flush.
In many toilet designs, water flows directly into the bowl and can also be dispersed into the rim of the toilet bowl. The water releases into the bowl rather quickly, with flow from the tank into the bowl typically lasting approximately two to four seconds. The water flows from the rim, and down a channel within the sides of the bowl, into the large hole at the bottom of the toilet, known as a siphon jet. The siphon jet releases most of the water into the siphon tube, initiating the siphon action. The siphoning action draws all the water and waste out the bowl, and into the siphon tube. The waste and water continues through the other end of a generally U-shaped siphon tube (also known as a trapway), and is then released into the wastewater or sewage drain line connected at the base of the toilet.
Once the tank is discharged during the flush, the flush valve is closed, and a floating mechanism, which has now dropped in the tank to some residual amount, initiates the opening of the fill valve. The fill valve provides fresh water to both the tank and the bowl through separate flows. Eventually, the tank fills with water to a high enough level to cause the float to rise, thus shutting off the fill valve. At this point, the flushing cycle is complete.
Government agencies have continually demanded that water use for flushing be reduced. Much of the focus in recent years has been to reduce the water demand required by toilet flushing operations. In order to illustrate this point, the amount of water used in a toilet for each flush has gradually been reduced by governmental agencies from 7 gallons/flush (prior to the 1950's), to 5.5 gallons/flush (by the end of the 1960's), to 3.5 gallons/flush (in the 1980's). The National Energy Policy Act of 1995 mandates that toilets sold in the United States can use water in an amount of 1.6 gallons/flush (6 liters/flush) or less.
One attempt in the art to produce a more reliable, more efficient and more powerful 1.6 gallon (6 liter) gravity flush toilet, known as a “high-performance toilet” (HPT), while overcoming the detriments in toilet technology by increasing the hydraulic energy available during the flushing operation, can be found in U.S. Pat. No. 6,901,610 entitled, “High Performance Valve Assembly For Toilets”; U.S. Pat. No. 6,728,975 entitled, “High Performance Flush Valve Assembly”; and U.S. Pat. No. 6,715,162 for “Toilet Assembly,” each of which is co-owned by the owner of the present application. Relevant portions of these patents to the extent they describe radiused inlet technology and general toilet tank operation and construction are incorporated herein by reference.
These patents disclose a flush valve assembly for a water tank of a toilet that includes a valve body secured thereto. The valve body has a base sleeve portion including a radiused inlet to increase the discharge coefficient of the valve opening. A flush cover member is coaxially and slidably mounted with respect to the valve body so that the valve opening is created therebetween when the flush cover member is removed from the valve body via reciprocating motion. The flush cover member is slidably movable between a first position, wherein the flush cover member is seated on the base sleeve portion of the valve body and thereby obstructs water flow through the valve opening, and a second position, wherein the second valve member is removed from the base sleeve portion of the valve body to permit water flow through the valve opening. A sealing member is provided to ensure a proper seal when the flush cover member is in the first position, and a guiding means is provided that properly aligns and guides the flush valve cover relative to the valve body. The flush valve assembly also includes a trip release mechanism that releases the effects of the flush lever on the flush cover member when the flush cover member reaches its second position, thereby returning the flush cover member to its first rest position prior to the flush lever returning to its own corresponding rest position. In this configuration, the disclosed flush valve assembly ensures compliance with the mandated water requirements and simultaneously provides enhanced cleanliness and waste removal capabilities. The flush valve assembly achieves these functions and also releases the effect of the flush lever so that the valve opening can close before the expiration of a regulatory minimum “hold down” time (1 second without exceeding the total water per flush mandate of 1.6 gallons (6 liters)).
Although these prior solutions noted in the above-patents effectively remove waste from toilet bowls within government guidelines, such guidelines no longer mandate a minimum “hold down time”. It is therefore desirable to provide the aforementioned benefits in a flush valve assembly having minimal moving parts for ease of manufacturing, installation, operation and maintenance. Such advantage should be incorporated in the flush valve assembly without compromising the water conservation benefits of the prior flush solutions.
Alternative technologies proposed for providing adequate flush valve efficiency for high-performance toilets may be found in U.S. Pat. No. 7,676,858 B2 which proposes the use of a flush valve that has a valve body with a valve seat that defines a flow passage having a portion of its interior flow profile that narrows in a non-linear manner away from the valve seat such that the inner surface of the valve seat in the non-linear portion can be defined by a polynomial expression, i.e., the valve body has a non-linearly curved inner surface.
U.S. Pat. No. 8,079,909 B2 discloses a flush valve that accomplishes water conservation and flush efficiency, as well as the performance goals noted above, by providing a more efficient combination of a radiused inlet and an optional elevated valve body. The flush valve assembly disclosed therein may also have a “poppet” or centrally aligned and guided buoyant float cover for the valve body. This particular design is highly effective if an upwardly buoyant and centrally guided flush cover is used, because the upward lifting of such a cover provides for water intake into the valve opening in a 360° configuration. That is, when the buoyant cover lifts, it allows for water to flow in from all directions into the valve opening for supplying water from the toilet tank to the toilet bowl.
Problems may be encountered when using an elevated valve body having an optimal radiused inlet designed to enhance flow and maximize hydraulic energy through the valve body with a standard flapper-type valve cover. Such standard flush valve covers are known in the art, readily available and it would be desirable to be able to use such commercially available covers with a high-efficiency valve body design. Flush valve body assemblies having a radiused inlet and elevated valve body, used with the above-noted, poppet, centrally-guided flush valve cover, are able to handle the increased efficiency and maximized flow through the valve body at reduced volumes of water so as to be useful as high-performance flush valves working with HPT toilets having toilet bowl designs and flush pathways that achieve the 1.6 gallons/flush water conservation standards, some of which may be qualified as high-efficiency toilets (HET) which provide effective flushing at as low as about 1.28 gallon per flush or even lower.
Using a standard two-inch diameter inlet, the flow rate through a high-efficiency flush valve designed to function with high-efficiency toilets (HETs) is very high, even though the volume in the toilet tank available for flushing is smaller than it might be in prior art traditional toilets. A traditional flush valve cover's performance used with such a valve body and a two-inch inlet becomes affected in terms of its ability to close when appropriate, sometimes closing prematurely, and in terms of its ability to re-open. This problem can be exacerbated in a radiused inlet valve body design, because the extension of the inlet opening due to the presence of the radius, which is optimized for high-efficiency flow through the valve body, can require an even larger sized flapper to cover the opening created by the radius which increases the force required to open the valve and actuate the flush. Furthermore, the high velocity flow enabled by the radiused inlet can counteract the buoyant force of the flapper and cause the valve to close prematurely. These factors combine to make it difficult to properly open and close a standard flapper on a valve assembly configured for use in an HPT or, preferably an HET and having an elevated valve body and radiused inlet, even in comparison to standard low profile, non-elevated flush valve bodies having standard flapper-type valve covers, for example, a commercially available Fluidmaster® Flush Valve Model 507.
Another problem encountered in prior art flush valve designs is that such flush valves, whether suitable for high-efficiency toilets or not, when optimized for flow design, have outlets which, when installed, introduce fluid flow directly into an inlet chamber of a toilet bowl having a lower floor which lies in a plane perpendicular to the flow coming out of the flush valve outlet. The impact of the contact against the bottom surface of the inlet chamber (which may be a manifold) of water under a high flow rate through the valve caused by flushing, introduces undesirable turbulence which reduces the hydraulic energy available from the water exiting the outlet of the flush valve. Prior art designs are available from the owner of the present application in which a fitting is used on the bottom of a flush valve outlet to divide and direct the flush valve outlet flow into two separate directions so as to introduce flow into the rim area and into the jet area of the toilet bowl. Such designs do avoid some of the impact issue, for certain particular high-efficiency toilet designs.
Based on the foregoing, there is a need in the art for a flush valve that can utilize the advantages of an elevated valve body having a radiused inlet suitable for use in HPTs, and preferably HETs, but which allows for adaptation and use of traditional flush valve covers (flappers). It would also be useful to provide a flush valve assembly configured by using pre-existing commercial flush valves having a lower valve body profile with new detachable sections to provide the same effect as an elevated valve body with a radiused inlet and which can make use of a standard flush valve cover.
There is also a need in the art for a flush valve that can provide an outlet opening that overcomes the potential hydraulic loss associated with impact on the floor of a toilet bowl inlet chamber but which can be used with any type of toilet bowl design having an inlet chamber therein.
U.S. Pat. No. 8,266,733 B2 discloses a flush valve that accomplishes water conservation and flush efficiency, as well as the performance goals noted above, by providing a more efficient combination of a radiused inlet and an optional elevated valve body where at least a portion of the valve body wall is downwardly linearly tapered. The publication also describes use of a bulb underneath the flush valve cover for the valve body to provide buoyancy, with the bulb sized and configured to fit within the inlet of the valve body. Although the bulb provides required buoyancy, it occupies space in the flow path when the valve is opened, which can reduce the flow rate below its maximum potential. When greater buoyancy is required, the size of the bulb must increase, further exasperating this drawback.
However, there remains a desire in the art to continue to increase the efficiency and performance of HPTs and HETs, and more particularly, for a higher efficiency flapper for a flush valve that can stay open longer at higher flush rates, which in turn, improves toilet performance.